Many electrical connectors conventionally are fabricated with a dielectric housing, such as molded of plastic material, for mounting a plurality of electrical terminals, such as stamped and formed metal contacts. One such connector may comprise a receptacle for mating with a plug connector, sometimes called female and male connector components. The terminals, likewise, may be formed as receptacle terminals for receiving pin terminals from the mating connector.
Electrical connectors of the character described above desirably have various characteristics such as reliable contact forces between the terminals in a transverse direction and, in some instances, anti-overstress protection for flexible portions of the stamped and formed terminals. It may be desirable for the receptacle connector and receptacle terminal to be capable of accepting a mating plug connector and pin terminal to be capable of accepting a mating plug connector and pin terminal from either direction, sometimes called "top and bottom" mating. When such connectors are used as headers, such as for surface mounting on a printed circuit board, it often is desirable that the connectors have a low profile in a direction transverse to the board.
One of the problems with electrical connectors or headers of the character described above involves solder contamination of the terminals during manufacture or processing of the connectors. In particular, when the terminals are female or receptacle terminals, solder tails are provided for insertion into holes in the printed circuit board. When the terminals are soldered to circuit traces or plated-through holes in the board, there is a tendency for some of the solder to flow into the housing which would contaminate or render inoperable the receptacle portion of the terminal. This is particular true of housings in which a complementary pin terminal is inserted into the receptacle terminal from below the printed circuit board.
For instance, a typical soldering method is called wave soldering, wherein the printed circuit board is passed through a molten solder wave that contacts the surface of the printed circuit board to establish solder connections between the solder tails of the receptacle terminal and the plated-through holes or the circuit traces on the printed circuit board surface. Normally, due to capilary action solder flows into the holes or any space left between the solder tails and the holes, with a possibility that the solder could enter the housing or build up on the solder tail and thus contaminate the receptacle portions of the terminals which would prevent a good electrical connection with a complementary pin terminals.
An example of an approach to prevent solder contamination as described above, is to provide a solder mask as shown in U.S. Pat. No. 4,750,889 to Ignasiak et al, dated June 14, 1988. This patent shows a through-board electrical component header having an integral solder mask means in the form of masking pins integrally attached to a body of the connector for insertion into the holes in the printed circuit board to completely block the openings and prevent solder from entering the holes. However, the solder masking pins, after the soldering process has been completed, must be removed in order to gain access to the receptacle portions of the terminals within the header body. In essence, the solder masking pins must be provided with some form of frangible means or portions to facilitate their removal. Such a system thus requires an additional step in the processing and mounting of the header to the printed circuit board before the assembly is ready for use. Such additional processing step adds to the expense and complexity of the assembly.
This invention is directed to solving the above problems by an improved solder masking technique which is processed using the same manufacturing procedures of non-solder masked connectors mounted to a printed circuit board.